The present invention relates to a method and an apparatus for outputting a multi-band image.
With progresses of photographing technologies over the recent years, a multi-channel photographing machine (a multi-band camera), particularly a photographing machine having channels of which the number is plural enough to restore spectral waveforms of a photographing object at an accuracy sufficient for practical use. This multi-band camera may be categorized as a camera capable of obtaining plural pieces of image data (multi-band image data) by photographing the same object with light beams in a plurality of different wavelength bands (multi-bands) light transmitting (over four kinds of light beams in the great majority of cases). This type of camera is disclosed on pp. 573˜578 in “Optics” 11(6) (1982), Miyagawa et al.
The data of the multi-band image photographed by this multi-band camera has a spectral waveform per pixel, and hence a variety of applications are expected.
Further, there are known a variety of methods of outputting the multi-band image data, and typical methods thereof are a method of reproducing a chromaticity of the object (which will hereinafter be called a chromaticity reproduction process) and a method of reproducing a spectral waveform of the object (which will hereinafter be termed a waveform reproduction process).
The prior art documents that propose methods of outputting the multi-band image data include Unexamined Published Japanese Patent Application No. 11-85952 for the chromaticity reproduction process and “Image Simulation Using Laser Color Printer”, Ohta et al., O plus E, pp. 57-64, (September 1981) for the waveform reproduction process.
There arise, however, the following problems inherent in the chromaticity reproduction process and the waveform reproduction process.
That is, the chromaticity reproduction process gives a high degree of the coincidence of the visual appearance between the original image and the duplicate image when reproducing the color under a limited light source, but has a problem in which the degree of the coincidence of the visual appearance largely declines if observing conditions such as an observation light source change.
By contrast, the waveform reproduction process gives a stable degree of the coincidence of the visual appearance which does not depend upon the observing conditions such as the observation light source, but has such a problem that the degree of the coincidence under then limited observing conditions is inferior to that of the chromaticity reproduction process.